Cross-over reed relay



Nov. 16, 1965 v J, oMP Ts ETAL 3,218,405

GROSS-OVEN REED RELAY Filed Oct. 9, 1962 FIG. 18

FIG. 1A

FIG. 3

g a e ii I:

FIG. 2

INVENTORS Robert J. Gomperfs Leo MS rengers Airy.

United States Patent 3,218,406 CROSS-OVER REED RELAY Robert J. Gomperts, Antwerp, and Leo M. Sprengers,

Lier, Belgium, assignors to Automatic Electric Laboratories, Inc., Northlake, I11., a corporation of Delaware Filed Oct. 9, 1962, Ser. No. 229,351 6 Claims. (Cl. 2110-87) This invention relates to electromagnetic devices and more specifically to cross-over type reed relays which have three terminals and are specifically designed to transfer an electrical load, for example, from one circuit to another, both of which are connected to the terminals of the relay.

A study of prior art relays of the above type reveals that they have certain design and operational drawbacks. For instance heretofore with this type relay a very critical gap dimension was incurred between the cooperating ends of the reeds. This resulted in a costly adjustment operation. In some designs more than one permanent magnet was required to achieve the proper operation between the armature or movable reed and the reeds it made contact with. Another disadvantage stemmed from the fact that the reeds themselves had to be made of specific resilient material as they were required to bend and cooperate with each other.

According to this invention these drawbacks are either substantially reduced or eliminated completely. For example the reeds in the preferred embodiment are not required to flex and bend as this is done by a single rocking armature element supported by a fixed reed. As a result the stress forces and the strain forces heretofore encountered on the envelope at the points where the reeds are secured to the envelope are eliminated. Moreover the relative position of the reeds are not as critical with the design of the invention as in the case of the prior art designs.

The principal object of the invention is to provide an improved design for the above type relay.

Another object of the invention is to provide such a relay design without the inclusion of critical air gap dimensions.

Another object of the invention is to provide a relay structure wherein virtually all contact bounce is eliminated.

Still another object of the invention is to provide a relay which when energized the applied field operates in the same direction as the field of a permanent magnet associated therewith.

In accordance with these objects the relay design features an elongated glass envelope which is preferably filled with a protective gas.

Also featured are three particular reeds, two of which extend through one end of the envelope and one which extends through an opposite end of the envelope. Each reed includes a terminal which extends externally of the capsule so as to be connectable to the corresponding external circuits which the relay is to control.

Connected to one reed, at its end extending within the capsule, is a permanent magnet. Connected to another reed at its corresponding end is a spring member which supports at its end an armature element. The armature element is made of magnetic material so as to respond to the influence of the magnetic field produced by the permanent magnet as well as the field set up by the coil which is wound about the external surface of the envelope.

The reed, spring member and armature element arrangement represents an important and distinctive feature of the invention. The spring provides the resilience necessary for the armature to rock or move between its Patented Nov. 16, 1965 two extreme positions, the permanent magnet and the particular reed. The armature, as a result of its configuration and composition, responds with extreme sensitivity without requiring critical contact gap adjustments. Also virtually no contact bounce is incurred due to the inclusion of the spring between the reed and armature element.

These and other objects and features will become more clearly understood upon reading the following detailed description which makes reference to the accompanying drawing of which:

FIG. 1A shows a plan view with a cutaway of the crossover reed relay according to the invention when it is in an unenergized state.

FIG. 1B shows a view similar to the view shown in FIG. 1A except that the relay is in an energized state.

FIG. 2 shows a modification to the relay shown in FIGS. 1A and 1B.

FIG. 3 shows a further modification of the embodiment shown in FIG. 1 and includes a plurality of crossover type reed switches within a sealed envelope.

Referring now to FIG. 1A and FIG. 1B of the drawing, the relay comprises an elongated glass or plastic envelope 10 which supports a coil 17 and three reeds 11, 12 and 13. It is to be understood that the term reed as used in the specification and the claims are not limited to those which are flat but also include round members and square wire rods. Moreover, according to the preferred embodiment the reeds are preferably rigid. The coil or winding 17 is shown schematically in the drawings but is wound directly on the envelope or, in an alternative scheme, can be wound on a spool (not shown) surrounding the envelope. The reeds 12 and 13 are supported at one end of the envelope whereas the reed 11 is supported at the opposite end thereof. The envelope of the relay is preferably formed after the reeds are placed in their respective position relative to each other. This sequence is an aid in getting an air tight seal between the reeds and the envelope in the finished product. It is to be noted that one end of each reed extends externally of the envelope and therefore acts as a terminal to the relay. Therefore, one or more external circuits (not shown), that are controllable by the relay can be connected to the terminals.

The opposite end of reed 11, reed 12 and reed 13 extends Within the envelope. More particularly, the internal end of reed 12 is connected to an end of permanent magnet 14. Magnet 14 is, for example, bar shaped and aligned along the longitudinal axis of reed 12. Also, the free end of the magnet reaches to approximately the halfway point of the length of the envelope. According to the particular embodiment shown the magnet is polarized so that its north pole is at its free end and the south pole at its connected end.

Connected integrally with the internal end of reed 13 is a spring 16 which supports an armature element 15. Spring 16 is preferably a thin round or fiat piece of resilient metal which enables the armature element 15 to pivot or rock with respect to the relatively fixed reed 11. As an alternative scheme the spring and reed can be made from one piece of resilient material.

Armature element 15 is preferably made of a magnetic material and is S-shaped to the extend that the legs thereof, designated by characters 15a and 1512, are substantially parallel. Therefore, leg 15a is aligned along the longitudinal axis of both spring 16 and reed 13, whereas leg 15b is offset with respect thereto. The end surface of leg 15]) is approximately flush with the free end of magnet 14. Both ends of the respective elements 14 and 15 overlap the plane of the internal end of reed 11. This overlap restricts the arc of travel of the armature element to one made between the permanent magnet on the one side and the reed 11 on the other side.

Reed 11 more specifically extends through an opposite end of envelope 10 from that of reeds 12 and 13 and is substantially aligned along a common axis with reed 13. As aforementioned the internal end of reed 11 overlaps the end of armature element 15 and thus makes contact with the same when the latter is attracted to reed 11 during energization of coil 17.

FIG. 2 shows a modification to the relay design shown in FIG. 1. This modification appears in the configuration of reed 111 Instead of a substantially straight reed like 11, reed 11 includes a branch segment 18 that extends perpendicular from the main axis of the reed. This branch segment preferably extends so far as to cover a projection of the end 15b of armature element 15 When the latter lies adjacent the permanent magnet 14, see for example FIG. 1A. The effect of this modification is observed primarily in the magnetic response and sensitivity of the relay which will receive elaboration in the following paragraphs.

When no external field is supplied and thus Winding 17 is not energized the armature element 15 is in the position shown in FIG. 1A. Under this condition permanent magnet 14 includes a magnetic field in armature element 15 in such a manner that the flux lines are closed in the direction abcd. The pull force (F) on this element as derived from the formula F A/u, where A=area and where u permeability of air, is then proportioned to If now an external magnetic field H is applied, by energization of winding 17, in the same direction as the magnetic axis of the permanent magnet, a second flux will be established which is superposed on the first flux and circulates through the armature element 15 and reed 11 in the direction cbe[]]. If the flux in the gap be is (p then the total force exerted on the moving member is proportional to The net flux through armature element 15 is and is caused by the difference of the permanent magnet field and the external applied magnetic field H As soon as becomes larger than the pull force on armature element 15 will change and start moving it from against permanent magnet 14 to reed 11. If the field gets larger, this negative retaining force will get larger and the moving member will move quicker, the balance of the forces still being proportional to whereby the permanent magnet is opposing the pull force 1%. Eventually armature element 15 takes up the position shown in FIG. 1B. However, when the external field H becomes so strong that the element 15 becomes magnetically saturated, then no longer does the permanent field oppose the movement of armature 15 towards reed 11, but actually repulses the armature since it is now magnetized in the same direction as the permanent magnet and the end 15b has also become a north. Once this happens, then the operation of the change-over becomes relatively independent of the air gaps be.

On release the action is somewhat different. When reducing the externally applied field, the magnetization of armature 15 decreases into the linear region. becomes larger than and the armature moves back against the permanent magnet 14.

As aforementioned the operating modification shown in FIG. 2 results in a change in operating characteristics. To illustrate, this configuration permits the saturation of the armature by an external field before the pull force between the armature 15 and reed 11 is larger than the pull force between the permanent magnet 14.- and the armature 15 exerted by the former. Consequently, as soon as saturation of the armature is reached by the external applied field qb the magnet 14 exerts a repulsive force on the armature. This motion is also assisted by the pull force of the flux which exerts in the gap be. The force carrying out the change-over is then proportional to from the beginning of its motion. This results in a relay which is very sensitive (saturation is reached quickly) and its action is not critical as far as gap dimension be is concerned.

IG. 3 demonstrates an arrangement which includes a plurality of the reed switches described in connection with FIGS. 1A and 1B. This arrangement is particularly suitable in relatively large switching arrays such as found, for example, in a central otfice to a telephone system. The variation of this arrangement from the aforedescribed arrangement is found in the surrounding of three reed sets 20 by a single encapsulation structure 10 Although only three sets are shown more may also be feasible.

The invention has been described in detail in connection with certain embodiments, however, it is to be understood this was done merely by way of example, and that there are still other modifications that could be made without departing from the scope of the invention as hereinafter claimed.

What is claimed is:

1. An electromagnetic device comprising:

a sealed elongated envelope having two ends;

a first reed and a second reed arranged substantially in parallel and extending through one end of said envelope, each of said reeds providing a terminal portion outside of said envelope and a free end portion inside of said envelope;

a third reed supported at the opposite end of said envelope, said reed being positioned so that the longitudinal axis thereof lies substantially coincident with the axis of said first reed, said reed also providing a terminal portion outside of said envelope and a contact end portion inside of said envelope;

an armature element pivotally mounted to said free end portion of said first reed and having an end offset with respect to said longitudinal axis of said first reed which normally lies in a spaced and operative relationship to said contact end portion;

a permanent magnet positioned Within said envelope and carried by said second reed and producing a magnetic field which holds said armature element in engagement therewith;

and winding means supported by said envelope which upon being energized produces a magnetic field which overcomes the flux of said permanent magnet and moves said armature element away from said permanent magnet and into engagement with said contact end portion.

2. An electromagnetic device as claimed in claim 1 wherein said offset armature portion is furthermore substantially S-shaped and oriented with respect to said reeds so that the one end thereof is aligned along an axis coincident with said longitudinal axis of said first reed and the opposite end thereof is aligned along an axis parallel thereto with said longitudinal axis.

3. An electromagnetic device comprising:

a sealed elongated envelope having two ends;

a first reed and a second reed arranged substantially in parallel and extending through one end of said envelope, each of said reeds providing a terminal portion outside of said envelope and a free end portion inside of said envelope;

a third reed supported at the opposite end of said envelope, said reed being positioned so that the longitudinal axis thereof lies substantially coincident With the axis of said first reed, and providing a terminal portion outside of said envelope and a contact end portion inside of said envelope;

an S-shaped armature element made of magnetically responsive material and pivotable with respect to said first reed, said armature element being normally in spaced and operative relationship to said contact end portion;

a leaf spring member made of resilient material and having two ends, one end being connected to the free end portion of said first reed and the other being connected to said armature element;

a permanent magnet positioned within said envelope and carried by said second reed and producing a magnetic field which holds said armature element in engagement therewith;

and winding means supported by said envelope which upon being energized produces a magnetic field which overcomes the flux of said permanent magnet and moves said armature element away from said permanent magnet and into engagement with said contact end portion.

4. A relay as claimed in claim 3 wherein said third reed includes furthermore a branch segment extending perpendicularly from the longitudinal axis of the reed and from a point intermediate the two ends of the reed to where the end of said branch segment covers the end projection of said armature element thereby aiding said applied field to effect movement of the armature from said permanent magnet to said third reed during energization of said winding.

5. A switching system comprising:

a sealed encapsulated structure having two ends;

a plurality of spaced reed sets supported by said encapuslated structure and each including a transfer contact arrangement; each of said sets having a first, second and third reed, said first and second reeds arranged substantially in parallel and extending through one end of said envelope thereby providing a terminal portion outside of said envelope and a free end portion inside of said envelope, said third reed supported at the opposite end of said envelope, said reed being positioned so that the longitudinal axis thereof lies substantially coincident with the axis of said first reed, said reed also providing a terminal portion outside of said envelope and a contact end portion inside of said envelope,

a plurality of S-shaped armature elements each pivot ally mounted to said free end portions of said first reeds and having an end offset with respect to said longitudinal axis of said first reeds which normally lie in spaced and operative relationship to said contact end portions;

a plurality of permanent magnets each positioned within said envelope and carried by said second reed and producing a magnetic field which holds a corresponding armature element in engagement therewith;

and winding means supported by said envelope which upon being energized produces a magnetic field which overcomes the flux of said permanent magnets and moves said armature elements away from said permanent magnets and into engagement with said contact end portions.

6. An electromagnetic device as claimed in claim 3, wherein said S-shaped armature element has two ends; one end being connected to said leaf spring and the other end being normally in contact with said permanent magnet, said two ends being in parallel with respect to each other and with respect to said first and second reed.

References Cited by the Examiner UNITED STATES PATENTS 2,535,400 12/ 1950 Ellwood 200-87 2,706,756 4/1955 Brewer 317-198 2,898,422 8/1959 Peek 200-144 2,957,961 10/1960 Juptner 200-144 3,117,202 1/1964 Werts 200-87 ROBERT K. SCHAEFER, Acting Primary Examiner.

BERNARD A. GILHEANY, Examiner. 

1. AN ELECTROMAGNETIC DEVICE COMPRISING: A SEALED ELONGATED ENVELOPE HAVING TWO ENDS; A FIRST REED AND A SECOND REED ARRANGED SUBSTANTIALLY IN PARALLEL AND EXTENDING THROUGH ONE END OF SAID ENVELOPE, EACH OF SAID REEDS PROVIDING A TERMINAL PORTION OUTSIDE OF SAID ENVELOPE AND A FREE END PORTION INSIDE OF SAID ENVELOPE; A THIRD REED SUPPORTED AT THE OPPOSITE END OF SAID ENVELOPE, SAID REED BEING POSITIONED SO THAT THE LONGITUDINAL AXIS THEREOF LIES SUBSTANTIALLY COINCIDENT WITH THE AXIS OF SAID FIRST REED, SAID REED ALSO PROVIDING A TERMINAL APORTION OUTSIDE OF SAID ENVELOPE AND A CONTACT END PORTION INSIDE OF SAID ENVELOPE; AN ARMATURE ELEMENT PIVOTALLY MOUNTED TO SAID FREE END PORTION OF SAID FIRST REED AND HAVING AN END OFFSET WITH RESPECT TO SAID LONGITUDINAL AXIS OF SAID FIRST REED WHICH NORMALLY LIES IN A SPACED AND OPERATIVE RELATIONSHIP TO SAID CONTACT END PORTION; A PERMANENT MAGNET POSITIONED WITHIN SAID ENVELOPE AND CARRIED BY SAID SECOND REED AND PRODUCING A MAGNETIC FIELD WHICH HOLDS SAID ARMATURE ELEMENT IN ENGAGEMENT THEREWITH; AND WINDING MEANS SUPPORTED BY SAID ENVELOPE WHICH UPON BEING ENERGIZED PRODUCES A MAGNETIC FIELD WHICH OVERCOMES THE FLUX OF SAID PERMANENT MAGNET AND MOVES SAID ARMATURE ELEMENT AWAY FROM SAID PERMANENT MAGNET AND INTO ENGAGEMENT WITH SAID CONTACT END PORTION. 